The present invention relates to a convertible ink scraper device for a reverse-rotatable mesh roller of the type which supplies ink to a plate cylinder of a printing unit and is capable of rotating selectively in normal and reverse directions, in a printing system changeable between two printing modes of which, one is monotone printing on both sides of a web, the other is two color printing on a one side of the web. The said printing system consists of a pair of printing units each having a plate cylinder and a impression cylinder, one of which is capable of rotating selectively in normal and reverse direction. More particularly, the invention relates to the ink scraper device being able to change a scraping position and direction of a doctor blade in which the distal edge thereof has been pressed on the peripheral surface of the mesh roller, corresponding to changed rotative directions of the mesh roller and the plate cylinder.
The doctor blade is provided so as to touch at the reverse angle against the rotative direction of the mesh roller, so that the ink on the peripheral surface thereof can be scraped by the doctor blade.
It is required to change not only a direction of the blade touching on the mesh roller, but also a position of the blade touching on the mesh roller, according to that the mesh roller can be rotated in normal and reverse direction.